The invention is based on an apparatus for damping courses of motion such as a shock absorber. Apparatuses for damping courses of motion are already known in which a damping piston divides a cylinder filled with pressure fluid into two work chambers that is provided with adjustable overflow openings. To this end, the two work chambers are each connected to one another crosswise and parallel to one another via oppositely oriented valves that allow a flow of the pressure fluid in only one direction. The amount of pressure fluid admitted by these valves at any one time is determined by corresponding triggering of the valves by means of a control device, as a function of suitably prepared sensor signals.
Especially in the field of motor vehicle construction, damping system development is directed to a purposeful adaptation of the damping characteristic to the particular driving status of the vehicle. The directional damper adjustment is effected, for example by means of valves adjustable as a function of control signals, as a function of sensor signals, which detect various driving status parameters (such as vehicle speed, vehicle inclination, transverse and vertical acceleration, and up-and-down, pitch and roll motions).
Among the control signals, a distinction can be made between so-called passive control signals, which are directed to slow, adaptive adaptation of the damping, for example as a function of the kind of ride desired by the driver, road conditions or the vehicle speed, and so-called active control signals, which are intended to bring about a direct change in the absolute speed of the vehicle chassis such as raising, lowering, pitch, roll within the shortest possible period of time. The entire damping system may be designed in such a way that the passive damping control increases or decreases the damping action in the same direction in terms of tension and compression, while the active damping control makes the damping asymmetrical as a function of external signals, or in other words varies the damping action in opposite directions in the compression and tension stage. The overall result is known as a semiactive damper system.
An apparauts for damping courses of motion that is specifically intended to operate in this way is described in German Offenlequnqsschrift No. 36 10 937. The control of the valves here is effected via two valve bodies, actuatable independently of one another, in the form of axially movable slides, which are located outside the actual shock absorber itself.